Slide fastener

ABSTRACT

A slide fastener comprises a pair of rows of continuous links of plastic material formed with coupling heads at adjacent inner edges of the rows. The coupling heads engage in coupling spaces formed by depressions in legs of the links. Projections formed on the legs prevent shifting of mounting threads toward the coupling spaces.

United States Patent [7 2] Inve ntor Bernd Porepp 16 Am Rebberg, 7764Wangen (Bodensee), Germany [21] Appl. No. 806,620

[22] Filed Mar. 12, 1969 [45] Patented Dec. 28, 1971 [32] Priority Mar.13, 1968 [3 3] Germany [54] SLIDE FASTENER 3 Claims, 6 Drawing Figs.

[52] U.S.C1 24/205.1, 24/205.13, 24/205.16 [51] 1nt.C1 ..A44b 19/12,A44b 19/34 [50] Field 01 Search 24/205.13 C, 205.16 C, 205.1 C, 205.13 C

[56] References Cited UNITED STATES PATENTS 3,149,388 9/1964 Wilcken..24/205.13 C UX 3,128,518 4/1964 Steingrubner.. .....24/205.l3CUX3,490,110 1/1970 Frohlich ..24/205.l3CUX Primary Examiner- Bernard A.Gelak Attorney-Polachek, Saulsbury & Hough ABSTRACT: A slide fastenercomprises a pair of rows of continuous links of plastic material formedwith coupling heads at adjacent inner edges of the rows. The couplingheads engage in coupling spaces formed by depressions in legs of thelinks. Projections formed on the legs prevent shifting of mountingthreads toward the coupling spaces.

PATENTEU M82819?! 55mm POIFEPP By Ema/roe @u/W rm 5 sum: FASTENERBACKGROUND OF THE INVENTION In known slide fasteners comprising rows ofcontinuous links made of a string of plastic material shaped to aflattened helical spring, individual convolutions or links of the pairof link rows are provided with coupling heads at their apexes facingeach other at adjacent edges of the rows. The heads merge intosuperposed link legs connected by loop portions of the convolutions. Thecoupling heads of the pair of link rows generally mutually engagealternately, directly one behind the other when the link rows arebrought into coupling engagement by a slide. In this the points of thecoupling surfaces engaging one behind the other form a continuous lineabout which the two link rows may tilt perpendicularly to the couplingplane, so that the coupling heads can easily be disengaged.

As is well known in the art each slide fastener half comprises a carrierribbon to which the link row is secured usually by sewing a seam ofchain stitches. Often the slide fastener is rendered unserviceablebecause the threads of the seam become displaced toward the couplingheads so that movement of the slide is prevented.

It is therefore, an object of the invention to prevent the possibilityof twisting the link rows about a longitudinal axis, and to reduce thepossibility of accidental separation of the coupling heads of the slidefastener.

Another object of the invention is to provide a slide fastener includingmeans for preventing the link rows from twisting relative to the planeof the slide fastener about a longitudinal axis and also to providemeans for preventing the displacement toward the coupling heads of theseam threads, by means of which the link rows are secured to theirrespective carrier ribbons.

SUMMARY OF THE INVENTION According to the invention, at least one of thesuperposed legs of each link in each row of links is provided with arecess or depression at its inner side. Each depression is spaced fromthe coupling head of each link. The depressions define spaces betweenthe legs of each link in each row thereof to receive the coupling headsof the links in the other link row.

The invention is an improvement over the prior art since the couplingpoints between the slide fastener halves do not follow a straight line,as was customary practice, but are spaced from each other, i.e.,alternately staggered in longitudinal direction along a zigzag line.Thus angular movements of the slide fastener halves about their couplingpoints are prevented, and the danger of unintentionally breaking thecoupling engagement is greatly reduced.

The secure grip of the interlocking engagement between the two slidefastener halves is further improved, in that both legs of each links ofboth link rows are provided with depressions disposed oppositely to eachother at the inner sides facing each other. These depressions defineenlarged coupling spaces in each link row for receiving the couplingheads of the other link row.

The invention involves a further improvement in that an outwardprojection and another depression are fonned in the legs of the linksand spaced from the coupling headQThe projection prevents shifting ofseam threads from the other depression. This prevents interference withmovement of the fastener slide.

The invention will now be described in detail in connection with theattached drawing showing several exemplified embodiments of theinvention. It is to be understood, however, that the invention shall notbe restricted to these embodiments, as changes or alterations areconceivable without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partial top view of a pairof link rows of a slide fastener in the form of flattened helicalsprings made of a string of plastic material;

FIG. 2 is a cross sectional view along the offset line IllI in FIG. 1 ona larger scale;

FIG. 3 is a further enlarged top view of a pair of coupled links of thepair of link rows of the slide fastener;

FIG. 4 is a schematic sectional view of a tool for producing thecoupling surfaces and the depression in the legs of the links;

FIG. 5 is a partial top view of a profiled string with a coined couplingsurface and a depression in the leg of the links; and

FIG. 6 is a cross-sectional view of a row of links of a slide fasteneremployed in the string shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, two rowsof slide fastener links 1 and 2 helically wound in counter directionsand provided with coupling heads 3 and 4 are shown. The legs, orconvolution portions 5, 6 and 7, 8 extending away from the couplingheads 3, 4 are disposed in spaced superposed relation to each other, ornearly contacting each other respectively, and then merge into theconnecting arcs or loops 9 and 10.

According to the invention the legs 5, 6 and 7, 8 of the pair of linkrows are provided with recesses or depressions 11, 12 and l3, l4oppositely disposed at the inner sides which face each other and areequally spaced from the coupling heads 3 and 4, An eye or coupling spaceis formed within which the free ends of the coupling heads 3, 4 arereceived in a coupling relationship when the link rows 1 and 2 of theslide fastener, which are each sewed to carrier ribbons l5 and 16, arebrought into meshing engagement by means of a slide (not shown). Thepoints of interlocking engagement of the coupling surfaces 3 and 4 ofthe pair of link rows with the coupling spaces defined by depressionsll, 12 and 13, 14 are spaced apart transversely relatively to thelongitudinal direction of the coupled slide fastener halves. The slidefastener links of the link rows cannot move in a vertical direction withrespect to the slide fastener plane. Also they cannot twist angularly toeach other and relative to the plane of coupling. Thus the possibilityof unintended breakage of the coupling is reduced. However, the slidefastener can be flexed in any direction.

In many cases it will suffice, as shown in FIG. 6, to merely provide onerecess or depression 12 or 14 in each one of legs 6 and 8 respectively,of the pair of link rows of the slide fastener. Recesses 11 and 13 willbe omitted. Recesses l2 and 14 will be located at inner sides of legs 6and 8 in order to provide coupling spaces for the coupling heads 3, 4 ofthe other link row. Thus twisting and accidental separation of thecoupled links will be prevented.

In shaping the string of plastic material to a flattened helical coil,one may proceed, according to FIGS. 4 and 5 in such a manner that thecoupling, heads 3 or 4 respectively, are formed by a pressing action ofa top die 17 provided with a coining projection I9 and a bottom die 18.The top die 17 is also provided with a second coining projection 20 oflesser height spaced relative to the first coining projection 19. Thissecond coining projection 20 serves to provide the recesses ordepressions 12 or 14 respectively, in the legs of the links. It is alsopossible to provide a recess 21 in the bottom die 18 opposite to thesecond coining projection 20 and to provide behind the recess 21 a thirdcoining projection 22 projecting slightly upwardly beyond the plane ofthe bottom die 18. Thereby the material of the string, displaced duringthe pressing action by the second coining projection 20, is urged intothe recess 21 and thickened by the third coining projection 22. Therebya small projection 23 of the string is formed andadjacent thereto arecess 24 is formed opposite from the depression 12. Recess 24 serves toreceive the lower thread loops of a chain stitch seam 25, forexample'The projection 23 prevents shifting of the seam in a directiontoward the depression and the coupling head which engages therein.

I claim:

1. A slide fastener mountable on a carrier ribbon, comprising a pair ofstrings of plastic material formed into a pair of longitudinallyparallel rows of links, inner edges of the rows being disposed adjacentto each other, each link having a pair of overlapping legs extending ina plane transversely of the row and terminating at a coupling head atthe inner edge of the row, said heads being widened to define oppositelydirected apical portions in the longitudinal direction of the rows, saidlegs engaging each other from substantially the head along a portion ofsaid legs, one of the legs of each link in each row being formed with adepression on the inner edge of said one leg facing its opposite leg andspaced from the head of the link by said engaging portion to define acoupling space with the other leg of the link to receive the couplinghead of another link in the other row.

2. A slide fastener as defined in claim I wherein the other leg of eachlink is formed with another depression facing the depression in said onelink for enlarging said coupling space to receive the coupling head ofsaid other link in said other row.

3. A slide fastener as defined in claim I, wherein another depression isformed in said one leg adjacent to the first named depression andfurther spaced from said head for engaging a thread of a seam in saidribbon, and a projection formed on said one leg between the twodepressions to prevent displacement of said thread from said otherdepression.

II l =0

1. A slide fastener mountable on a carrier ribbon, comprising a pair ofstrings of plastic material formed into a pair of longitudinallyparallel rows of links, inner edges of the rows being disposed adjacentto each other, each link in each now having a pair of overlapping legsextending in a plane transversely of the row and terminating at acoupling head at the inner edge of the row, said heads being widened todefine oppositely directed apical portions in the longitudinal directionof the rows, said legs engaging each other from substantially the headalong a portion of said legs, one of the legs of each link in each rowbeing formed with a depression on the inner edge of said one leg facingits opposite leg and spaced from the head of the link by said engagingportion to define a coupling space with the other leg of the link toreceive the coupling head of another link in the other row.
 2. A slidefastener as defined in claim 1 wherein the other leg of each link isformed with another depression facing the depression in said one linkfor enlarging said coupling space to receive the coupling head of saidother link in said other row.
 3. A slide fastener as defined in claim 1,wherein another depression is formed in said one leg adjacent to thefirst named depression and further spaced from said head for engaging athread of a seam in said ribbon, and a projection formed on said one legbetween the two depressions to prevent displacement of said thread fromsaid other depression.